Comp Cam Spring Selection - Chevelle Tech
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post #1 of 8 (permalink) Old Jan 17th, 20, 11:30 PM Thread Starter
Scott
 
Join Date: Dec 2019
Location: Fond du Lac, WI
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Comp Cam Spring Selection

Building a 496 and got a Comp 11-443-8 roller with 294/300 with .540"/.560" lift. Comp suggested 120-140 lbs on the seat and 320-350 Lbs open. I would like to use a set of AFR 305 heads for torque. They have a pocket of 1.750" with installed height of 1.950". Springs on these heads are too big. Seems cheaper to replace springs than buy bare heads and build them from scratch.
I can't use the Comp spring chart and find anything light enough closed without being too light open. Sent them an email so we'll see what they find.

My '66 has AC with a fan housing really close to the rocker cover. Can't use big enough covers for roller rockers. The adjusting studs are too tall. I need to keep the spring tight to use a set of roller tip rockers. I'm not even sure the AFR heads will fit with my aluminum marine covers.

Anyone been down this road?
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post #2 of 8 (permalink) Old Jan 18th, 20, 4:02 AM
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Marcus
 
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Re: Comp Cam Spring Selection

Quote:
Originally Posted by Scott Mack View Post
Building a 496 and got a Comp 11-443-8 roller with 294/300 with .540"/.560" lift. Comp suggested 120-140 lbs on the seat and 320-350 Lbs open. I would like to use a set of AFR 305 heads for torque. They have a pocket of 1.750" with installed height of 1.950". Springs on these heads are too big. Seems cheaper to replace springs than buy bare heads and build them from scratch.
I can't use the Comp spring chart and find anything light enough closed without being too light open. Sent them an email so we'll see what they find.

My '66 has AC with a fan housing really close to the rocker cover. Can't use big enough covers for roller rockers. The adjusting studs are too tall. I need to keep the spring tight to use a set of roller tip rockers. I'm not even sure the AFR heads will fit with my aluminum marine covers.

Anyone been down this road?
Use the recomended 930-16 spring and a .060 thick locator like 4776-16. Just check so the locator id is enough so it fits over the guide.
With the locator you will get 1.890” installed height. But use a valve spring mic so you get it right.
Or check with Mike Lewis aka wolfplace

https://www.chevelles.com/forums/mem...wolfplace.html

https://www.lewisracingengines.com/

He can probably order with correct springs from AFR.

With that cam and enough spring for it I would not use roller tip rockers the pressures will be on the edge of what they can take without breaking. Crower makes shorter polylocks
https://www.summitracing.com/parts/cro-86050s-16/ with them you usually can fit comp 1620-16 or other full roller rockers under oem valve covers.
There are also ”cheater” covers avaible.
https://www.ss396.com/part/ALS-1065XT.html
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post #3 of 8 (permalink) Old Jan 18th, 20, 11:38 AM
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Lew
 
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Re: Comp Cam Spring Selection

Also take a look at the 4700-16 spring cup. The ID will also vary on your valve guide diameter and dictate a certain part number. On a friends build we also went with the 930-16 spring (1.55 OD spring install height around 1.90 inches - install at 150 pounds open like 390 pounds) as it has a little more pressure to keep the heavy valves in place. You may need to see what the max spring pressure the rocker arms you are talking about can take as sounds like you are limited.

Last edited by Lew540; Jan 18th, 20 at 11:41 AM. Reason: adding stuff
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post #4 of 8 (permalink) Old Jan 18th, 20, 2:54 PM Thread Starter
Scott
 
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Re: Comp Cam Spring Selection

Marcus & Lew, thanks for the info. Not sure where you looked up spring info but I spent some time on the Comps site and didn't see it. I like the idea of using the locator/cup to reduce spring size required. Now I can add new seals to the list. If it was as easy as replacing the springs I could do that without pulling the seal off the valve. I'll see what Comp comes back with but your numbers come in pretty darn close.
I've been working with Competition Products in Wisconsin, about 30 minutes drive for me. They said the best AFR can do is a special order 175# closed/450# open for hyd. rollers.

Thinking I might be on the edge of the roller tip limits, I will be putting a screen in the valley. I had already removed the casting flash in that area. I checked out the Crower Polylocks and they are short at .865" and just might work. Looked at ARP and they are 1.2" tall, not a chance. I have a set of stainless roller rockers and can do some fit-up before pulling that trigger.

I simply cant use a taller rocker cover. Distance between the cover and AC fan is just enough to sneak the heater hose through with a stock head. I even thought about dropping a spacer between the cover and head for assembly reasons. This just doubles my risk for leaks. I'm afraid the AFR might be taller in this area already. No room to drop the engine in the frame either. All this to use roller rockers...

Thanks guys for your input and experience. I've said it before, this site ROCKS!
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post #5 of 8 (permalink) Old Jan 18th, 20, 3:24 PM
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Marcus
 
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Re: Comp Cam Spring Selection

Quote:
Originally Posted by Scott Mack View Post
Marcus & Lew, thanks for the info. Not sure where you looked up spring info but I spent some time on the Comps site and didn't see it. I like the idea of using the locator/cup to reduce spring size required. Now I can add new seals to the list. If it was as easy as replacing the springs I could do that without pulling the seal off the valve. I'll see what Comp comes back with but your numbers come in pretty darn close.
I've been working with Competition Products in Wisconsin, about 30 minutes drive for me. They said the best AFR can do is a special order 175# closed/450# open for hyd. rollers.

Thinking I might be on the edge of the roller tip limits, I will be putting a screen in the valley. I had already removed the casting flash in that area. I checked out the Crower Polylocks and they are short at .865" and just might work. Looked at ARP and they are 1.2" tall, not a chance. I have a set of stainless roller rockers and can do some fit-up before pulling that trigger.

I simply cant use a taller rocker cover. Distance between the cover and AC fan is just enough to sneak the heater hose through with a stock head. I even thought about dropping a spacer between the cover and head for assembly reasons. This just doubles my risk for leaks. I'm afraid the AFR might be taller in this area already. No room to drop the engine in the frame either. All this to use roller rockers...

Thanks guys for your input and experience. I've said it before, this site ROCKS!

The info is on comp cams homepage under recomended components.
https://www.compcams.com/xtreme-ener...k-396-454.html

If comp doesnt have a solution

Comp 939-16 may work but has higher open pressare.

Brodix has a spring BT 120121 that should work but 16.99 each

Howard 98652 may also work

Lunati 73121-16 should also work

But I think the locator an 930-16 is best solution if you are careful its possible to remove and reuse the seals.

Chevelle Malibu ss 64
489 BB with parts from Lewis racing
Alumitech radiator with dual spals
Th 400 Edge 9.5" converter
57 3/4” wide 12 bolt: Eaton posi, Us gear 3.31, Toms KA 33 splines axles
Malibu ss 64 is online now  
post #6 of 8 (permalink) Old Jan 18th, 20, 3:31 PM Thread Starter
Scott
 
Join Date: Dec 2019
Location: Fond du Lac, WI
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Re: Comp Cam Spring Selection

My wife gets angry when I can't find stuff.

Maybe it's me.

Nah....

Thanks Again!
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post #7 of 8 (permalink) Old Jan 19th, 20, 2:23 AM
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Mike
 
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Re: Comp Cam Spring Selection

I can have the heads done by AFR with a spring that will be close to what you are asking for so you wouldn't need to change anything
At your .560 lift it would be about 140/370 & there would be no extra charge for the spring exchange

PM or email me if I can help....
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post #8 of 8 (permalink) Old Jan 19th, 20, 3:26 AM Thread Starter
Scott
 
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Re: Comp Cam Spring Selection

Quote:
Originally Posted by Wolfplace View Post
I can have the heads done by AFR with a spring that will be close to what you are asking for so you wouldn't need to change anything
At your .560 lift it would be about 140/370 & there would be no extra charge for the spring exchange

PM or email me if I can help....
Thanks Mike, Look for my Email.
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